Thai authorities have detained five foreigners who crewed a mystery aircraft which made an emergency landing at Don Mueang and impounded 35 tonnes of heavy war weaponry that were loaded on the plane, reported TNA news agency.

More than 100 Thai security personnel searched a Russian-built IL-76 military air transport bearing the designation AWG 732 when aircraft, which flew from North Korea asked permission to land at Bangkok's domestic Don Mueang airport to refill fuel.

The Thai authorities found massive numbers of the shoulder-launched missile weapon including rocket-propelled grenades (RPG), anti-aircraft SAM (surface to air missiles) and ammunition.

One Belarussian and four Kazakhstani nationals who were on board were arrested.

The Thai authorities said the airplane was believed to be carrying the weapons to Sri Lanka, where a long civil war recently ended.

According to the authorities, the plane earlier arrived at Don Mueang airport once in the morning for refueling before departing for North Korea after it had loaded with the heavy weaponry and asked to refuel again at the airport at 4pm.

The move was the result of cooperation between Thai and American units as the Thai authorities were inform by the United States that the plane was carring heavy weapons which had led to impounding of the airplane and weapons.

The five suspects were sent to Thailand's Police Crime Suppression Division for questioning while the impounded weapons were reportedly transferred in the military trucks to a depot in Nakhon Sawan, a province some two hours’ drive from Bangkok.